Farm Goat Escape

You're asleep and you have a dream. In your dream you see a goat standing alone in a farm locked up. The landlord of the farm went to a nearby town and he won't be back for quite long. So you need to help the poor goat to escape from there. The lock won't open until you pour some lubricant oil on it. Collect the clues and solve puzzles to find the lubricant.